Are Mushrooms High FODMAP? (2025 Low FODMAP Guide)

If you adore mushrooms but live with IBS, SIBO, or chronic bloating, you’ve probably wondered: are mushrooms high FODMAP? And do you really need to avoid them altogether?

Here’s the comforting truth:

• Many fresh mushrooms are high FODMAP in typical portions.
• But some varieties are beautifully low FODMAP, and others can be enjoyed in small, measured serves.
• And thanks to recent updates from Monash University, we now have a clearer understanding of which mushrooms contain which FODMAPs and how to use them safely.

In this freshly updated 2025 guide, you’ll find:

• A clear explanation of which mushrooms are high FODMAP
• The best low FODMAP mushroom options
• How Monash updates affect mushroom choices
• Practical tips to enjoy mushrooms without symptoms
• A warm, friendly FAQ (schema-ready)

Take a breath; you don’t have to give up mushrooms. You just need the right information.

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Are mushrooms high FODMAP? A quick answer

Most fresh mushrooms contain significant levels of mannitol, a polyol (sugar alcohol) known for causing digestive symptoms in people with IBS. Some mushrooms also contain fructans, another FODMAP group that can be problematic in larger servings.

Here’s a simple breakdown:

1. White/button mushrooms (fresh)
   • High FODMAP in typical serves due to mannitol and fructans.
   • Tiny amounts can be low FODMAP.
2. Chestnut and cremini mushrooms
   • Similar to button mushrooms: high FODMAP in normal serves.
   • Small serves may be tolerated.
3. Portobello mushrooms
   • High in mannitol in regular portions.
   • Tiny serves may be tolerated, and they’re now commonly used for mannitol reintroduction challenges.
4. Oyster mushrooms
   • Naturally low FODMAP in generous serves.
   • One of the best everyday options.
5. Canned button mushrooms (drained)
   • Low FODMAP in much larger serves than fresh.
   • The canning liquid pulls out some of the FODMAPs.
6. Dried mushrooms (shiitake, porcini, etc.)
   • Very small portions can be low FODMAP, but amounts rise quickly.

So, are mushrooms high FODMAP?
Some are, yes, but others are perfectly compatible with a low FODMAP diet.

Why mushrooms cause symptoms: mannitol & fructans

The role of mannitol

Most mushrooms are naturally rich in mannitol, a type of polyol. In many people with IBS, polyols:

• Draw water into the intestine
• Ferment quickly
• Trigger bloating, gas, cramping, and loose stools

This is why some people feel very sensitive to fresh mushrooms, especially in larger servings.

The role of fructans

Button mushrooms (and some other varieties) also contain fructans, making them “double FODMAP” foods. This is one reason they’re no longer recommended as the food used to challenge mannitol during reintroduction.

Different people react differently based on:

• The total FODMAP load of the meal
• Stress levels
• Gut sensitivity
• Whether SIBO is also present

Remember: FODMAP tolerance is deeply personal, and the diet is meant to help you discover your unique limits, not follow rigid rules forever.

What’s new? Mushroom updates from Monash

Since 2017, Monash University has revised several food listings, including mushrooms. The key modern updates include:

• Button mushrooms are now recognised as containing both mannitol and fructans.
  This means they’re not ideal for testing one FODMAP group on its own.
• Portobello mushrooms are now preferred for testing mannitol tolerance.
  Their FODMAP profile makes them more suitable for structured reintroduction.

These updates don’t drastically change which mushrooms are high or low FODMAP, but they do change how to use mushrooms in the elimination and reintroduction phases.

FODMAP content of common mushrooms

Let’s go through the mushroom varieties you’ll see most often in UK and European shops.

1. Fresh button, chestnut, cremini & portobello mushrooms

These mushrooms all belong to the same species, so their FODMAP profiles are similar.

• High FODMAP in normal portions
• High in mannitol, and in the case of button mushrooms, fructans too
• Very small serves (just a few slices) may be low FODMAP
• Not ideal during the elimination phase

Simple recommendation:
Avoid fresh button/portobello/chestnut mushrooms during elimination unless you are very comfortable weighing extremely small portions.

Later, during reintroduction, portobello mushrooms may be used for mannitol challenge testing.

2. Oyster mushrooms, the best low FODMAP option

Oyster mushrooms are naturally low in FODMAPs, even in generous portions. They’re soft, mildly earthy, and easy to use in:

• Stir-fries
• Risottos
• Pasta dishes
• Omelettes
• Soups

You can usually enjoy a full serving without worrying about exceeding the low FODMAP threshold.

If you’ve been missing mushrooms, oyster mushrooms are your most reliable friend.

3. Canned button mushrooms (drained)

Canning dramatically changes the FODMAP profile because mannitol and fructans leach into the brine.

Once drained (and ideally rinsed):

• Canned mushrooms become low FODMAP
• Serving sizes are much larger than with fresh mushrooms
• They’re a practical option for cooking during elimination

Use them in:

• Pasta sauces
• Casseroles
• Risotto
• Frittatas

Just make sure the can contains plain mushrooms in brine (not garlic or onion).

4. Enoki, shimeji, black fungus & other niche mushrooms

Some less common mushrooms can be low FODMAP in small or moderate portions:

• Enoki mushrooms: small serves may be low FODMAP.
• Shimeji mushrooms: often tolerated well in modest serves.
• Black fungus / wood ear mushrooms: typically low FODMAP in larger portions.

Always double-check serving sizes and start gently if you’re sensitive.

5. Dried mushrooms (shiitake, porcini, chanterelles)

Because dried mushrooms are concentrated, their FODMAP content rises sharply with portion size.

General rules:

• Very tiny serves are low FODMAP
• Larger amounts quickly become moderate or high FODMAP
• They work beautifully as flavour enhancers

Tips for using dried mushrooms safely:

• Use a small, measured amount
• Soak them, then lift the mushrooms out of the water
• Discard most of the soaking liquid to reduce FODMAP load

How to enjoy mushrooms safely on a low FODMAP diet

Step 1: Choose the right type

Best options during elimination:

• Oyster mushrooms
• Canned button mushrooms (drained and rinsed)
• Tiny portions of dried mushrooms (if you’re comfortable measuring)

Avoid or limit:

• Button mushrooms
• Chestnut mushrooms
• Portobello mushrooms
• Shiitake mushrooms
• Mixed mushroom dishes where portion sizes are unknown

Later in reintroduction, you can test your favourites in carefully structured amounts.

Step 2: Mind your portion sizes

FODMAPs increase with serving size. A mushroom that is low FODMAP at 10 g can be high FODMAP at 50–100 g.

To stay safe:

• Weigh portions at first
• Keep only one potential FODMAP “risk item” per meal
• Start with half of the recommended low FODMAP serve if your gut is especially sensitive

Step 3: Cook them in a gentle way

You can make mushrooms easier on your digestion by:

• Cooking them thoroughly
• Using low FODMAP aromatics (garlic-infused oil, spring onion greens)
• Pairing them with soothing ingredients like olive oil and herbs
• Avoiding rich or fatty sauces on sensitive days
• Discarding soaking water when using dried mushrooms

Using mushrooms during FODMAP reintroduction

Once you’ve had a few weeks of symptom improvement, mushrooms become a useful tool for reintroduction.

Because of recent Monash updates:

• Portobello mushrooms are now used to challenge mannitol
• Button mushrooms are no longer recommended for this purpose because they also contain fructans

A typical challenge looks like:

• Day 1: small serve
• Day 2: medium serve
• Day 3: large serve

All while keeping the rest of your diet strictly low FODMAP.

After formal reintroduction, you can test your favourite mushrooms (e.g., chestnut or button) in real-world portions to understand your personal limits.

So… can you enjoy mushrooms on a low FODMAP diet?

Yes, with thoughtful choices.

Here’s the summary:

• High FODMAP in typical serves:
  • Fresh button, chestnut, cremini, portobello, fresh shiitake
• Low FODMAP in generous serves:
  • Oyster mushrooms
  • Canned, drained button mushrooms
• Low FODMAP in tiny flavour portions:
  • Dried shiitake, porcini, chanterelles

You don’t have to eliminate mushrooms forever. You just need to choose the right type and portion, especially early in the diet. Over time, you may find you can reintroduce more than you expected.

You deserve a relationship with food that feels confident and calm, and mushrooms can absolutely be part of that journey.

FAQ: Are Mushrooms High FODMAP? (schema-ready)